This application is directed to improvements in coffee grinders. More particularly, this application is directed to improvements for coffee grinders for the home market.
Generally speaking, coffee grinders for the home must be relatively simple and reliable in operation, and yet durable and reasonably maintenance free. These goals must be accomplished within strict budgetary considerations, making it possible to design, assemble and market a coffee grinder at a price suitable for home use.
Generally speaking, a number of problems must be overcome in properly grinding coffee. Initially, different types of coffee and different types of coffee brewing methods require different grind sizes of the coffee. While commercially ground coffee is available in several grinds, many consumers prefer the flavor of freshly ground beans. Moreover, many coffee lovers mix a number of different beans to obtain a desired flavor blend.
Coffee lovers know that coffee begins to lose flavor and aroma as soon as it is ground. In fact, roasted bean coffee has a shelf life approximately much longer than preground coffee.
In general, the finer the grind of the coffee, the greater the surface area exposed to water during brewing and the more rapid the rate of flavor extraction. A coarse grind exposes less surface and is therefore more appropriate for longer brewing cycles. On the other hand, a grind too fine tends to result in a more bitter flavor. Generally speaking then, the correct coffee grind is one that permits the water to pass through the coffee grounds in the correct amount of time with the minimum amount of sediment.
The grinding of coffee requires a grinding apparatus which has sufficient power to fully grind the coffee to desired size, and yet does not bruise, burn or abrade the coffee bean. That is, the coffee bean should ideally pass through the grinder relatively rapidly, and be quickly and efficiently ground to the desired finished size. Unfortunately, many coffee grinding machines presently on the market for home use fail to achieve these ends reliably.
Many of these home coffee grinders utilize blades or so-called burrs to grind the coffee. However, most of these machines utilize a rotary action of the blades or burrs and, in order to apply sufficient force to the beans, utilize relatively high rotational speeds. For example, typical home machines on the market utilize rotational motor speeds of anywhere from 20,000 rpm to as high as 29,500 rpm. These rotational speeds, together with the types and sizes of blades and/or burrs used in these machines, produce an effective blade or burr speed (surface feet per minute) of anywhere from on the order of 9,200 sfpm to as high as 17,900 sfpm. A few machines do utilize lower motor shaft speeds and/or effective blade or other cutting surface speeds. However, we have found none of the prior home market grinders able to achieve grinds to CBC (Coffee Brewing Council) specifications.
The relatively high rotational speeds of most grinders tend to crush and abrade the beans in such a way that considerable heat builds up and burning of the beans occurs during grinding. Such heat build-up and subsequent burning of the beans can adversely affect their flavor.
As an additional matter, many home market machines are difficult to effectively clean, and allow excessive chaff and ground coffee to build up in the grinding areas and mechanisms. This chaff and ground coffee can, of course, deteriorate and become stale over time, and thus compromise the flavor of freshly ground coffee being processed through the grinder.